In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11...In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11.4 nm, and 6.5 nm are experimentally studied. All of the EL spectra present a similar blue-shift under the low-level current injection,and then turns to a red-shift tendency when the current increases to a specific value, which is defined as the turning point.The value of this turning point differs from one another for the three InGaN/GaN MQW samples. Sample A, which has the GaN barrier thickness of 21.3 nm, shows the highest current injection level at the turning point as well as the largest value of blue-shift. It indicates that sample A has the maximum intensity of the polarization field. The red-shift of the EL spectra results from the vertical electron leakage in InGaN/GaN MQWs and the corresponding self-heating effect under the high-level current injection. As a result, it is an effective approach to evaluate the polarization field in the InGaN/GaN MQW structures by using the injection current level at the turning point and the blue-shift of the EL spectra profiles.展开更多
The effects of different potential well depths, well widths and barrier widths on energy band of multiple quantum well (MQW) structures are discussed in detail based on Kronig-Penny model. The results show that if the...The effects of different potential well depths, well widths and barrier widths on energy band of multiple quantum well (MQW) structures are discussed in detail based on Kronig-Penny model. The results show that if the well and barrier width stay unchanged, the first and second band gaps increase linearly with the well depth. When the well depth is constant, the first and second band gaps increase exponentially with the barrier width in a wide well. However, in narrow well one, the second band gap saturates when the barrier width is wide enough. On condition that the well and barrier have equal width, the first band gap decreases exponentially with well-barrier width while the second gap still shows an exponential increase with the width. These results are insightful for the design of MQW structure optoelectronic devices.展开更多
利用LASTIP软件理论分析了有源区量子阱数目对不同组分的In Ga As Sb/Al Ga As Sb 2μm半导体激光器能带、电子与空穴浓度分布以及辐射复合率等性能参数的影响。研究表明：量子阱的个数是影响激光器件性能的关键参数,需要综合分析和优...利用LASTIP软件理论分析了有源区量子阱数目对不同组分的In Ga As Sb/Al Ga As Sb 2μm半导体激光器能带、电子与空穴浓度分布以及辐射复合率等性能参数的影响。研究表明：量子阱的个数是影响激光器件性能的关键参数,需要综合分析和优化。量子阱数太少时,量子阱对电子束缚能力弱,电子在p层中泄漏明显,辐射复合率低。量子阱数过多时,载流子在阱内分配不均匀,p型层中电子浓度升高,器件内损耗加大,辐射复合率下降。结合对外延材料质量的分析,In Ga As Sb/Al Ga As Sb半导体激光器有源区最优量子阱数目为2~3。该研究结果可合理地解释已有实验报道,并为2μm半导体激光器结构设计提供理论依据。展开更多
利用新型全固源分子束外延技术 ,对 1 .5 5 μm波段的 In As P/ In Ga As P应变多量子阱结构的生长进行了研究。实验表明 ,较低的生长温度或较大的 / 束流比有利于提高应变多量子阱材料的结构质量 ,而生长温度对材料的光学特性有较...利用新型全固源分子束外延技术 ,对 1 .5 5 μm波段的 In As P/ In Ga As P应变多量子阱结构的生长进行了研究。实验表明 ,较低的生长温度或较大的 / 束流比有利于提高应变多量子阱材料的结构质量 ,而生长温度对材料的光学特性有较大的影响。在此基础上生长了分别限制多量子阱激光器结构 ,制作的氧化物条形宽接触激光器实现了室温脉冲工作 ,激射波长为 1 5 63 nm,阈值电流密度为 1 .4k A/ cm2 。这是国际上首次基于全固源分子束外延的 1 .5 5 μm波段 In As P/ In Ga As展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0400803 and 2016YFB0401801)the National Natural Science Foundation of China(Grant Nos.61674138,61674139,61604145,61574135,and 61574134)。
文摘In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11.4 nm, and 6.5 nm are experimentally studied. All of the EL spectra present a similar blue-shift under the low-level current injection,and then turns to a red-shift tendency when the current increases to a specific value, which is defined as the turning point.The value of this turning point differs from one another for the three InGaN/GaN MQW samples. Sample A, which has the GaN barrier thickness of 21.3 nm, shows the highest current injection level at the turning point as well as the largest value of blue-shift. It indicates that sample A has the maximum intensity of the polarization field. The red-shift of the EL spectra results from the vertical electron leakage in InGaN/GaN MQWs and the corresponding self-heating effect under the high-level current injection. As a result, it is an effective approach to evaluate the polarization field in the InGaN/GaN MQW structures by using the injection current level at the turning point and the blue-shift of the EL spectra profiles.
文摘The effects of different potential well depths, well widths and barrier widths on energy band of multiple quantum well (MQW) structures are discussed in detail based on Kronig-Penny model. The results show that if the well and barrier width stay unchanged, the first and second band gaps increase linearly with the well depth. When the well depth is constant, the first and second band gaps increase exponentially with the barrier width in a wide well. However, in narrow well one, the second band gap saturates when the barrier width is wide enough. On condition that the well and barrier have equal width, the first band gap decreases exponentially with well-barrier width while the second gap still shows an exponential increase with the width. These results are insightful for the design of MQW structure optoelectronic devices.
文摘利用LASTIP软件理论分析了有源区量子阱数目对不同组分的In Ga As Sb/Al Ga As Sb 2μm半导体激光器能带、电子与空穴浓度分布以及辐射复合率等性能参数的影响。研究表明：量子阱的个数是影响激光器件性能的关键参数,需要综合分析和优化。量子阱数太少时,量子阱对电子束缚能力弱,电子在p层中泄漏明显,辐射复合率低。量子阱数过多时,载流子在阱内分配不均匀,p型层中电子浓度升高,器件内损耗加大,辐射复合率下降。结合对外延材料质量的分析,In Ga As Sb/Al Ga As Sb半导体激光器有源区最优量子阱数目为2~3。该研究结果可合理地解释已有实验报道,并为2μm半导体激光器结构设计提供理论依据。
文摘利用新型全固源分子束外延技术 ,对 1 .5 5 μm波段的 In As P/ In Ga As P应变多量子阱结构的生长进行了研究。实验表明 ,较低的生长温度或较大的 / 束流比有利于提高应变多量子阱材料的结构质量 ,而生长温度对材料的光学特性有较大的影响。在此基础上生长了分别限制多量子阱激光器结构 ,制作的氧化物条形宽接触激光器实现了室温脉冲工作 ,激射波长为 1 5 63 nm,阈值电流密度为 1 .4k A/ cm2 。这是国际上首次基于全固源分子束外延的 1 .5 5 μm波段 In As P/ In Ga As
